1. Technical Field
This invention relates to a limited slip differential mechanism for effectively transferring torque to both of a coaxially aligned pair of axles of a wheeled vehicle. More specifically it relates to a compact limited slip differential mechanism which includes an externally controllable electromagnetically operated clutch mechanism that provides a variable resistance to excessive relative rotation of the axles irrespective of the rate of relative rotation and of the output shaft torque level.
2. Prior Art
Many of the prior art differential gear mechanisms were not only bulky but were also excessively complicated and thus costly to manufacture. These problems were often compounded by the addition of various means to limit differential rotation of the vehicle axles automatically in the event of loss of traction between the road surface and one of the wheels. In most instances the amount of resistance to relative rotation provided by the automatically controlled slip limiting differentials was entirely dependent upon or directly proportioned to the rate of relative rotation and the output shaft torque level. Even though these devices were a vast improvement over open differentials, they did not satisfy all conditions. This was particularly true with respect to conditions involving incipient wheel slippage, low wheel slippage and low slipping wheel torque.
Accordingly, it is an object of this invention to solve these problem and provide a compact, durable and effective differential gear assembly which is economical to produce and is capable of controlling the resistance to differential rotation of the vehicle axles irrespective of the rate of their relative rotation and torque levels.
It is another object of this invention to more effectively control the resistance to differential rotation by providing an electromagnetically variable first force resisting differential rotation and a cam operated supplemental second force resisting any continuing differential rotation which occurs after the first force has been applied and for its duration.